Abstract

The energy profiles for radical dissociation of the lowest triplet state of various symmetric and non-symmetric ketones have been computed using the MINDO/3 method and employing configuration interaction. The results of radical dissociation of thioformaldehyde were also examined. In each case, the activation barrier arises from an avoided crossing between two states of different symmetry. Our analysis reveals that the perpendicular motion of the carbonyl carbon is an important component in the reaction coordinate.